WebGL: Mark framebuffer-render-to-layer as failing

Mixing 3D color attachments with 2D depth stencils in D3D11 is not
valid. This test often produces flaky results due to invalid render
target state.

Mark it as failing so that ANGLE can always return unsupported
framebuffer status for the subset of tests that do this behaviour.

Bug: chromium:1251626
Change-Id: Ic9a6591b7b97fd74d704bd71c81ac5d41758bbb7
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/5245747
Reviewed-by: Peng Huang <penghuang@chromium.org>
Commit-Queue: Geoff Lang <geofflang@chromium.org>
Cr-Commit-Position: refs/heads/main@{#1255332}